Color photography



May i2, 931 L, DUFAY L856l COLOR PHOTOGRAPHY Filed March 8, 1929 GREEN Ream* BLUE-VIOLET Patented May l2, l1931 UNITED STATES PATENT OFI-ics LOUIS DUFAY, QE 'VEBBAILLES, FRANCE, ASSIGNOB T0 ABOLD WADE, O17' LONDON,

' ENGLAND conos. rnoroemnz k VApplication med Iarch, 1929, Serial No. 845.604, and in Great Britain August 8, v1928.

This invention consists of improvements in or relating to color photography. One object is to enable photographs in natural colors to be taken or reproduced on non-inflammable films, viz. iilms made from cellulose acetate or similar cellulose ester of an organic acid. Another object is to enable photography in natural colors to be applied w successfully to the cinematograph.

Hitherto, suggestions have been made for the application to iilms of Celluloid, or of gelatine, of dots, lines or geometrical at-v terns-made up of two, three or more co ors. rlhe lm thus prepared was coated with a light-sensitized layer after a suitable varnishing.

According to this invention a process of makin a risulti-color` screen for color photograp y or cinematogra hy includes the step of applying to a iilm o cellulose acetate, or similar cellulose ester ot an organic acid, a solution ot collodion, or similar solution of cellulose nitrate, alone, or in admixture `with soningor plasticizing agents, before applying the dyes or-colors. Alternatively, said solution may itseli contain a dye.

Further, according to this invention said solution may rorman eective hond `with the film, and dyes applied to the i'rl. treated with such solution may penetrate into the r Fw rlhis invention also includes a support tor a multicolor screen comprising in combination a layer oi cellulose 'acetata'or similar cellulose ester et an organic acid and a deposited layer thereon of cellulose nitrate alone or in aixture with softening or plasticizing agents.

rl`his invention also includes a process of making a multi-colour screen for color hotography, or cinematography, in which t ere is apeplied to a' dyed suport, as above descri d, fatty resists ena ing the portions of the support which are not protected by the reists to be decoloured and dyed with another co or,

The said resists may be removed and a fresh application of resists made to enable se the port1ons of the support which are not the protected to be again d'ecoloured and dyed with another color. l

The invention relates to the manufacture and use of multicolor vscreens and sensitized ilms for color photography and cinematography, whether the films be master films (e. g. ne atives) or reproduced films (e. g. positivesg Further features of the invention will appear from the following description with reference to the accompanying drawings Figures v1 4, which itshould be understood are diagrammatic only, of one method o carrying the invention into eect in the production of cinematograph iilms in natural colorsv:

A cellulose acetate lm is produced in any known vva ,but preferably, according to the methods dgscribed in United States applications ot H. J. Hands, Ser. llo. 300,932 and Ser. No. 238,150. rlhe thickness ci the lm may be about 0.0055 inch, and the nlm is con'- veniently cut to a Width of about l0 inches. rllhe clean nlm, from a bobhin, is led through a coatin apparatuapreferably of the type describe in the U. S. application of Charles lBonamico, Serial No. 345,568, led March 8,

1929. The object is to apply on one side of the n lm aa line layer of collodion oi a definite and uniform thichess (Figure l), and in the present example the collodion embodies a een dye. llt isthis collodi *n coating which 1s to receive the various dyes, and in daten. mining the composition of the collodion and the thichess of the layer the determining factor isthat the ultimate coloured portions shall 've the correct spectrum absorption. A 2% solution of industrial collodion, and a 5% solution .of industrial collodion, are mixed together in such quantitiesas to aord the required viscosit, The proportions have to he varied'to suit t e similar conditions. The collodion mixture is dyed green vWith an alcoholicv solution of malachite osition o the dye may be, for example, alcohol 100 parts, malachite green 4 parts auramine 6.7 parts. The com osition of the'collodion .mixture may be, or example, collotemperature, humidity, and y een and of auramine. The comdion mixture 30 c. c., dye solution 2 o. c. For instance, in practice it has been found convenient to apply this solution in such a thickness thatan area of 100 c. long, by 26 c. wide, takes 22 to 25 c. c. Thus, the thickness of the layer is about .01 millimetre wet, i. e. .0002 to .0005 millimetro when dry. The collodion layer could be put on uncoloured and thereafter dyed.

The film Ydyed uniformly green all over is thenV led through a printing machine by means of which extremely ne parallel lines of greasy ink (intended to act subsequently as fatty resists) are printed upon it. The

' printing is edected by means of a small engraved steel roller having (in one case) lines and 15 intervening grooves per millimetre. -In theV example, the lines Were at 23 to the airis oi the cylinder. The iilm at this stage eirhibits 15 clear' green lines c and 15 opaque greasy lines d (green underneath) per millimetro, hoth kinds oi line seing of about the same Width (Figure 2). Alfter an interoi about an hour, to let the ink dry., the film is led in succession (a) over a bath which hleaches and dissolves out-the green dye from only the clear spaces, leaving nnattaclred the green lines protected by the ink. The composition oiD this bath :is-alcohol l00-parts, potassium hydrate (10% aqueous solution) 2 parte, acetone 4 parts, (o) over an inlring roller which applies a red dye to the spaces hetween the ink line. ln this example the red dyeis basic red N intra (Kuhlmann) 8% solution in alcohol. The iilm is thoroughly trashed "with Water tof-remove the excess oi' dye. (c) The film is passed through solvent cleansing hath of benzene and is hru'shed hy roller brushes Within the benzene to Arenier/'ls the inlr lines, leaving exposed the clear green lines. Y'

The lilm is again led (when dry) through the printing machine which produces parallel lines oi greasy ink e (Figure 3)-, as before, but Ythis time at right angles to those formerly made. ln other words, the lines are at 0701 to the airis ois the cylinder and at right angles to the redand green lines. After an interval ior the ink to dry, the lilm is led in succession (a) over a bath Which bleaches and dissolves out the-red and greendye from only the clear spaces `between the greasy lines, (t) Yover an inking roller which applies a violet dye which dyes the interlined spaces. The violet dye containscrystal violet (4% solution: in alcohol) 80 parts, and malachite green (8% solution in alcohol) parts. (c) rll`he ilm is again led through a solvent cleansing bath of benzene and is brushed by roller-brushes Within the,V benzene to remove the ink lines (Figure 4);. The film is then dried, is coated with a suitable substraturn (such as a thin layer of gelatine and a thin layer of varnish) and is thereafter coated With a layer oil sensitiz'edemulsion (a panchromatic emulsion) The bath referred to above under (a) conveniently comprises :alcohol YYY100 parts, potassium hydrate Y(10% aqueous solution) l part, acetone 10 parts, water 6 parts.

I claim: e

1. A method of making a multicolour photographic screen consisting in applying toa film of a cellulose ester 'of an organic acid a coating of cellulose nitrate in solution, drying the coating and thereafter treating said coating to produce therein a multipiicity of differently-coloured regions.

2. A method of making a multicolour photographic screen consisting in applying to a Vfilm of cellulose acetate a coating of cellulose nitrate in solution, drying the coating and thereafter treating said coating to produce therein a multiplicity of diilerentlycoloured regions. V E Y 3. A. method of making a multicolour photographic screen consisting in applying to a film oli a cellulose ester of an organic acid a coating ot cellulose nitrate in solution in adminture with a plasticizing agent, drying the coating and thereafter treating said coating to produce therein a multiplicity oi dinierently-coloured regions.

t. A method Yoi' making a multicolour photographic screen consisting in applying to lili?. ot cellulose acetatey a coating oit cellulose nitrate in solution in admixture with a plasticising agent, drying the coating and thereafter treatingV said coating to produce therein a multiplicity of diHerently-coloured regions. e Y,

5. l rnc- ""iod ot making a multicolour photo "raphic screen consisting in applying to a m, of cellulose ester ci an organic Yacid a coating of cellulose nitrate in solution in adminture With a dye, drying the coating and thereafter treating said coating to produce therein a multiplicity of differentlycoloured re "ions, Y

0. met od of making a multicolour photographic screen consisting in applying to a. iilm ci cellulose acetate a coating of cellulose nitrate in solution in admixture with a dye, drying the coating and thereafter treating said coating to Yproduce therein a multiplicity oi" differently-coloured regions.

7. method of making a multicolor photographic screen consisting in applying to a hlm of a cellulose ester of an organic acid a coating off cellulose nitrate in solution in advmixture with a dye, Vdrying' the coating, ap-

YVplyingthereto a fatty resist, dec-olouring those not protected by said resist, dyeing said parts with another color and removing the resist.

' 8. Amethod of making` a multicolour photographic screen consisting in Yapplying to a iilm of a cellulose ester of an organic acid a coating of cellulose nitrate in solution in admiirture with a dye, drying the coating, ap-

plying thereto a fatty resist in a pattern o lll asoaeei parallel strips, decolourin those parts not v protected by said resist, yeing said parts with another color, removing the resist, applying further resist in a pattern of parallel strips transverse to the direction of those formerly applied, decolouring the portions not protected by the resist, dyeing them with a third color, and removing the resist.

9.- A method of making a multicolour photographic screen consisting in applying to a film of cellulose acetate a coa-ting of cellulose nitrate in solution in admixture with a dye, drying the coating, applying thereto a fatty resist, decolouring those parts not protected by said resist, dyeing said parts with another color and removing the resist.

l0. A method of making a multicolour photographic screen consisting in applying to a, film of cellulose acetate a coating of cellulose nitrate in solution in admixture With a plastioizing agent and with a dye, drying the coating, applying thereto a fatty resist decolouring those parts not protected by said resist, dyeing said parts with another color and removing the resist.

11. A multicolour photographic screen comprising a film of acellulose ester of an organic acid having va deposited coating thereon of cellulose nitrate which is dyed in different colors in dierent parts thereof.

12. A multicolour photographic. screen comprising a film of cellulose acetate having a deposited coating thereon et cellulose nitrate which is dyed in different colors in different parts thereof.

13. A multicolour photographic screen comprising a iilm of cellulose acetate having a deposited coating thereon o'f cellulose nitrate in admixture With a plasticizing agent which is dyed in dierent colors in dierent parts thereof.

In testimony whereof l ax m signature.

LOUIS UFAY. 

